DESCRIPTION: Messenger RNA (mRNA) degradation is a process that plays an important role in the regulation of gene expression. mRNA decay rates vary greatly and can be modulated in response to environmental signals. Many studies have demonstrated that mRNA turnover can be linked to translation. One pathway that has been extensively investigated and clearly exemplifies the linked to translation. One pathway that has been extensively investigated and clearly exemplifies the link between translation and mRNA turnover is the nonsense-mediated mRNA decay pathway. The major aims of this grant are as follows. First, to rigorously define the sequences required for stimulation of decay following a nonsense codon. Second, to perform several genetic screens to identify trans acting components that function in nonsense mediated decay. Third, to utilize a series of genetic and biochemical assays to gather information about the structure and function of those trans-acting factors.